I just posted this over in the Elsa Babe forum in a reply to a question about hosiery for my 102cm, but I guess it's worth repeating here.
viewtopic.php?p=2464581#p2464581
I usually shop AliExpress for the girls.
Opaque/semi transparent hose and fishnets can be found by searching for "Pantyhose Ballet Dance Tights for Girls" and "Fishnet Pantyhose for Girls".
https://www.aliexpress.us/item/22518327 ... pt=glo2usa
https://www.aliexpress.us/item/32568052 ... 6004831%21
Size-wise, the 90cm and 100cm sizes go on without too much struggling. The fit is always a little weird from the crotch up. The kids these are meant for don't have much difference in their measurements from hips to waist to bust. With Pepper's more hourglass figure, these tend to fit at the hip and then can be too wide and too tall at the waist. I usually just roll the waist band over to shorten them and then pin the waist band tighter at the back to decease the width. For the price and trouble, it's not worth trying to do any sewn alterations on most hosiery.
Here's the fishnet body suit you've seen Pepper and Neko Marty in.
https://www.aliexpress.us/item/32568053 ... pt=glo2usa
It's made for a "full size" body but when it arrives it is tiny and not stretched out. It's a pretty good fit except that the crotch will hang down way below the crotch. You need some special materials to machine sew this fabric to avoid jamming your machine. I recommend just hand stitching it. It's only about an inch wide and down there you really don't see much of it so a "rough" sewing job won't detract very much.
Regular sized knee high stocking are pretty good "nylon stockings" on the 102cm and the 90cm. The band at the top of the stocking holds them up so they don't really require a garter belt. But a garter belt can really complete the look. You won't find any garters on "children's" searches so find the smallest ladies size you can find and be prepared to do a little sewing or pinning.
A search thorough "Girls Ballet Dancewear" will get you some tops, skirts, and leotards.
https://www.aliexpress.us/w/wholesale-G ... l.search.0
For Pepper I usually get a T4 or 100cm size. Again, pinning at the back may be necessary. Finding the appropriate 90cm size is still a work in progress.
Lastly, a lot of women's tops like simple t-shirt cuts (not fancy tailored/button down styles) in XS and XXS sizes can be used as full dresses on the 102cm. Depending on the stretch of the material, you may need to add a belt to give the garment a waist.